Lignomat Mini-Ligno E/D - Pin Moisture Meter - Moisture Detector for Wood Floors, Woodworking, Building and House Maintenance - Humidity Detection & Moist Meter for Wood Walls, Pallets, Firewood

The Lignomat Moisture Meter Mini-Ligno E/D proved to be very accurate when tested on various hardwoods. It's sturdy, well made and a perfect size for portability. Are there more accurate and highly rated meters? Of course but for the price, you can't beat it.

WHY MOISTURE MEASUREMENTS ARE IMPORTANT. Wood has an amazing ability to shrink when it is dry and expand (swell) when it is wet. I learned this hard way some 25 years ago when I built a nice rustic table from boards with unknown moisture content... and found a few weeks later that my nicely aligned boards shrank and formed unsightly 3/16" gaps between them. Reportedly, 90% of hardwood floor installation problems are related to moisture content. Usually, moisture content is not something that one can see or feel without a tool, and any error can be quite costly. According to NWFA (National Wood Flooring Association), two conditions should be met. Moisture content of hardwood and subfloor should be within the typical range for the area where it is installed, usually in the range 6-8%, up to 8-13% in the coastal areas. The difference between the moisture content of the hardwood planks and subfloor should be within 4% for narrow planks and 2% for wide planks. If these conditions are not met, one may have to wait until the wood equilibrates with the environment.HOW THE MOISTURE CONTENT IS MEASURED. There are two ways to measure moisture content. The most common one is based on wood resistivity. measured between two pins pressed into the wood. Dry wood has much higher resistivity (typically in the range of hundreds of megaohms) than wet wood (in the range of kilohms). The second method is contactless. The wood acts as a dielectric between two electrodes in the back of the gauge, thus forming a capacitor. A radio frequency current (in the range of hundreds of kHz) flows through this capacitor, and its capacitance (which depends on moisture level) is measured. The advantage of a contactless meter is that it does not leave pin marks on the wood and can go to a lower moisture content readings than resistance meters. However, it is more difficult to accurately measure capacitance than resistivity. Consequently, contactless meters are are less accurate at the low end but just as accurate or even more accurate than resistance meters at the high end (but their price at the high end is really high).WHAT IS THE DIFFERENCE BETWEEN THE CHEAP AND THE EXPENSIVE. This is the usual big question - should I buy a $30 moisture meter or a $300 one? What do I gain from buying the most expensive one, and what do I lose if I go with the cheap? My research on this topic revealed the following factors.1. All pin-based gauges use the same principle: they measure voltage applied to the pins and the current flowing between the pins to calculate resistivity. In order to do this calculation accurately, you need to accurately measure current and voltage. Additionally, due to high resistance of dry wood, it is really hard to measure at or below 6%. In the cheapest meters, you get the cheapest components (esp. low end analog to digital converters) and a poor measurement accuracy. Consider this fact: even the best tools just barely deliver the accuracy required to meet the NWFA requirements. According to the statistical study of P.J.Wilson published in Forest Products Journal in 1999, high end pin meters have accuracy (standard deviation) of 1.5% in the units of moisture content (compared to 2% to 4% range recommended by NWFA). I expect a lot higher errors with the low end tools, and some of them can be useless because they are so inaccurate.2. Moisture content may vary from the surface into the depth of the plank. For instance, a board which was rained on may be wet on the surface but dry in the center. Ideally, one has to get pin penetration depth of 1/4 to 1/5 of the thickness of the wood piece to get an average reading. Low-end gauges may not have pins suitable for deep penetration, whereas high end gauges have stronger pins and pin holders and oftentimes come with external pin holders (probes) connected via a cable. Additionally, they frequently come with isolated pins in which only the tip of the pin is conductive; this helps to eliminate the effect of near-surface conductivity in the wood. This is critical in wood manufacturing. Fortunately, the difference between shallow and deep penetration readings are usually very small with typical hardwood projects, where wood is fairly dry. This mini Ligno comes with two sets of pins for two different depths, 5 mm and 10 mm, but they do not appear super strong.3. Moisture readings depend on the temperature of the wood. You typically get 0.5% difference for each 10F (5 degrees C) deviation from the standard room temperature. The most high end meters get built-in temperature sensor and do corrections automatically. Middle range tools come with a correction table. Low end tools may use a standard calibration for a typical room temperature of 70F and no correction option at all. This mini Ligno does not have a built-in correction but it has a correction table in the manual.4. Wood species dependence. Usually, moisture meters use Pacific NW Douglas Fir as a calibration reference, and apply correction coefficients for each specific type of wood (this has to be entered manually, there is no way for the tool to determine what wood it is measuring). While domestic species are relatively similar, exotic hardwoods may deviate from Douglas Fir quite substantially. The good news is that at moisture level below 10% (which is the typical range recommended for installation), the differences between most domestic species is within 1-2% moisture content which is about the same as error level of the meter itself. Therefore, these differences can oftentimes be neglected for the range between 6% and 10%.The higher end is the tool, the more sophisticated is the correction procedure. This low end mini Lingos like this one group all 54 wood species into two groups, with the assumption that variation within each group is small. Higher end tools may group wood types into 5-6 groups. Finally, one can have individual calibration for each specific wood type (up to 20-40 species). It does not really cost manufacturers that much to incorporate higher level of calibration details into the tool (in some cases, it is just the cost of the paper on which the conversion table is printed), but it results in a substantial price premium for the tools with many types of wood species listed individually. Of course, in order to take advantage of all this accuracy, you might also want to have deep penetrating (isolated) tips and built-in temperature correction and perhaps higher level electronic circuitry, and it all comes together as a unit in the $300+ price range. This advantage of high end models comes at a price of complexity which most people might not like: just imagine, you face a task of measuring moisture of walnut. OK, with an advanced tool, you may have a choice of African, American, European, New Guinea, and Queensland Walnut (go figure which one you got). Then, you need to measure at several different depths... Make sure temperature correction is done... Then, average multiple readings... Will an average user do this all? I suppose this is why not everyone needs (or will properly use) the most accurate tool.4. Ability to store and average readings. It is generally recommended to take multiple readings across different boxes of hardwood or different subfloor locations and average them. Higher end tools can do it for you. Not a big factor for DYI, but might be a nice thing to have for a pro.SUMMING IT UP: It appears that this model of Mini-Ligno falls into the low-mid range of moisture meters. It has adequate electronics to measure resistivity with acceptable accuracy for successful woodwork and hardwood flooring. It has a very basic correction for wood species (just two groups). It does not have a built-in temperature correction, but it comes with a correction table in the manual. It does come with two sets of pins, but it requires some work to exchange them. My guess is that one can probably expect errors up to 2-4% of absolute moisture content (meaning you can likely may get a reading of 11% for the wood with moisture content of 8%). This gets one in a ballpark of marginally acceptable accuracy for determination if moisture content of the wood is in the NWFA range, and works reasonably well to check how well the moisture content of the hardwood and subfloor is matched.THE BOTTOM LINE: This is probably the cheapest mid-range gauge which you can buy to use as a reasonably accurate measurement tool for working with wood. Lignomat is considered a brand name in the world of moisture meters and has been in business since 1975. Mini-Ligno line is their pocket-size lower end line of meters, and this is one of the lowest end tools in the mini Ligno series. It appears to be just above the low-end boundary which separates tools from useless toys with pins, glowing numbers, and buttons. It is not quite as sophisticated, accurate, and robust to the daily abuse as higher end ($200 - $500) models from Delmhorst or Wagner, but it is about accurate enough for most common wood species for in-home hardwood installations and woodworking. Very easy to use (just one button to press). Very easy to carry around due to its small size. Not a big financial loss if you break it or lose it. Relatively good price to value ratio for DYI people (although I am still puzzled what is in there that warrants the $100 price). You still get only (on a relative scale of moisture meters) as much as you paid for (and the readings can certainly be off by a couple percent or more for less standard wood species), but you might not even need anything more than this for the standard task of determining if the hardwood and subfloor are ready for installation. I've seen professionals using them, and they are certainly good enough for DYI folks.Higher end mini Ligno models with the letter C have a connector for external probe. For extra $10 or so, one can get an S/D model which can also measure moisture level in drywall (which might be useful for home inspectors inspecting flooded buildings).Almost twice more expensive DX model gets a lot more accurate with the built-in correction for 65 individual wood species grouped into 20 groups (and - I am guessing here - might also have more precise electronic components). This will get you an improvement by 1% or 2% in accuracy for dry wood and even more for wet wood.Wood groups listed in the manual of E/D and S/D include (there is no Group 1, just 2 and 3):Group 2: Abachi, Afrormosia, Bamboo, Beech, Cedar, Cumary, Cypress, Dogwood, Gonzales Alves, Ikoro, Jatoba, Koa, Locust, Oak, Poplar, Ramin, Rosewood, Teak, Wenge, Zebra Wood, Hardboard, OSB, waferboard.Group 3: Alder, Ash, Aspen, Balsa, Basswood, Birch, Cherry, Cottonwood, Cypress, Elm, Douglas Fir, Gum, Hemlock, Hickory, Kempas, Larch, Lauan, Mahogany, Maple, Meranti, Merbau, Myrtlewood, European Oak, Pine, Redwood, Spruce, Teak, Tigerwood, Walnut, and particleboard.

It is an axcellently built and very precise tools. Very easy to use. I tested it on old wood - 7-8 q, on freshly cut wood - 30 - 35%, on water - soaked Wood - 45% plus (it blinks over maximum value) and it shows corect values. When repeating the measurements it indicated the same same value. On self test - 6% for test 1, 18-25% for test 2 with fingers on pins. Well done, Lignomat.

It seems accurate but alsoTo change the battery or pins you take it apart and when you do the circuit board comes out. It isn't attached to the case. There is no real battery compartment and the battery has one of those crappy connectors that require a bit of force to take off the 9 v battery. This is a bit of an issue when the wires are so thin and could easily be broken. Plus while you are changing them the loose circuit board is moving around. When it is all tight it works great but I did expect a little better quality.

This moisture meter works reasonably well for the price range.